Smaller predators, such as invasive Pacific lionfish that escaped from aquariums, have begun to fill in the niches left by the bigger fish, sending the coral reef community into flux.

"Healthy and intact coral reefs need large predatory fish in order to continue to provide human societies with food and with beauty," study author Chris Stallings, a researcher at Florida State University's Coastal and Marine Laboratory, told National Geographic News.

The loss of predators is part of the "litany of doom and despair" that Duke University's Pimm said befalls the environmental movement every year. "We are still chopping down the forest, we are still dumping a lot of greenhouse gases in the atmosphere, we are still overfishing," he said.